Horst Miracle Probes

[86 Cavalcade]

Since I have owned this coach the tank monitors have never worked on the black and gray water tanks. The black tank always showed full, the gray tank either full or 2/3 full, and the fresh water tank normally showed 1/3 full. Someone else on the group had installed these Horst probes by cutting holes in the white utility bay panel. I did not have a problem with doing this but I wanted to seal up the 10" X 12" hole cut in the floor below the shower drain trap. Because I have been on this quest to seal up the worst of these air holes I needed to remove this white panel. I used a mirror to look at the back side of the panel and decided that I needed to cut 3 of the plastic water lines. I had purchased a ratcheting plastic tubing cutter and cut the 3 water lines. After cutting the water lines I had the panel out in a few minutes. The fresh water cock will unscrew but I was not able to unscrew mine because it had been installed with some kind of thread dope that was like concrete. If you can unscrew this fitting you would only have to cut 2 water lines to get it out. I was able to seal up the shower hole using some OSB board, and finished the hole sealing with some expanding foam.

I drilled the 3/8" holes in the fresh water, gray water, and the black water tanks using a Forstner bit with a stop on it. After drilling the holes I tried to look thru the holes in the black and gray tanks expecting to see stuff stuck on the walls, but, I could only see black plastic. I installed 4 new probes in each of the black and gray tanks, but, I could not install the top probe in the fresh water tank because the aluminum support for the black and gray tanks was in the way. When I had finished installing the new probes I pushed the test button on my monitor and it showed all the tanks were empty. I filled the fresh water tank and it showed each level as the tank was filling. I then drained the tank and as the water level was dropping below the new probes the monitor was indicating accurately. We are going to a campground for a few days and I am hoping the black and gray water tanks will work. I took a bunch of pictures as I was doing this and am attaching 2. Picture #7 shows the gray water tanks with the new probes installed, picture #8 shows shows the OSB board sealing up the shower hole. I sealed the water tubing run and the cutout in the OSB board with some expanding cell foam. I have several more pictures and if anyone is interested in trying to remove this white utility bay panel you can contact me and I will send the pictures with an explanation of how I got the panel out. George R. 2001 Diplomat 40' PBD

[AFChap]

I installed Horst probes a couple of years ago. I had some problems in the beginning, but got them working, and they seem to get even better with age.

Beware sealing up those cable/plumbing access holes (depending on how you will be using your rig of course) ...they normally are calculated into air circulation to help your basement tanks/plumbing receive some heat in cold weather.